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000
FXUS66 KEKA 262222
AFDEKA

AREA FORECAST DISCUSSION
National Weather Service Eureka CA
322 PM PDT Fri Apr 26 2024

.SYNOPSIS...Cooler temperatures and drier weather are expected
tonight after a few lingering evening showers. Chance for light
rain will return by midday Saturday, followed by drier weather and
below temperatures Sunday into early next week.

&&

.DISCUSSION...Shower activity has been steadily diminishing
this afternoon as an unseasonably cold upper trough progressed
into the Great Basin. Robust NW flow aloft on the backside of the
trough will diminish tonight as a ridge builds aloft, stability
increases and deep mixing subsides. Shallow moist air will likely
result low cloud cover and perhaps fog in the interior valleys
tonight. Precipitation totals over the last 24 to 36 hours varied
widely. For interior Del Norte, 1.72-2.19 occurred, while southern
Mendocino (Ukiah) and southern Lake received no measurable rain.
Blustery W-NW winds will persist across southern Lake and southern
Mendocino into this evening with peak gusts from 20 to 40 mph, highest
over the exposed ridges and channeled terrain of Lake County.

Another frontal system with a long westerly fetch of high PWATS
(125-150% of normal) will approach on Saturday. Some light rain
may occur (30-50% chance for a few hundredths) primarily north of
Cape Mendocino. Amounts most likely will not exceed a tenth in 6
hours though a HREF has 60% chance over the higher elevations of
Del Norte and Humboldt. A few hundredths appear more probable
(60% chance).

Subfreezing temperatures are highly probable (80% chance) for the
mountains above 3000-3500 feet tonight and Saturday morning.
Probabilities for valleys to freeze are much less certain with
only a 20-40% chance for the typical cold valleys in Trinity,
eastern Humboldt and NE Mendocino. Fog and low clouds will form in
the valleys and hinder the longwave cooling.

Otherwise, broad and flat ridging is forecast to build offshore
as a series of shortwave troughs brush the northern portion of
the area, mostly Del Norte county, with periodic precipitation
chances into mid week. Low-amplitude westerly flow will most
likely keep temperatures on the mild side and near seasonal
normals through early next week. Greater uncertainty arises mid to
late week with potential for flow amplification over the NE
Pacific and above normal interior temperatures. DB


&&

.AVIATION...Widespread MVFR/IFR conditions prevailed across
the region as another weather disturbance moved through NW
California this morning. Marginal flight impacts occurred at
coastal airports; this included light to moderate rain and
associated mist (fog). Inland locations were mostly VFR,
occasionally fluctuating into MVFR in the mid- morning...and
little reported rain. More importantly, some locales reported WNW
breezy to gusty winds this afternoon. Across the region, model
guidances are suggesting general improvement (post frontal) before
another "not so dynamic" weather system began to influence the
coastal terminals overnight. The result will be deteriorating
conditions in late morning into afternoon; this includes low
Cig/Vis and rain. /TA

&&

.MARINE...Light to gentle breezes in the northern waters are
forecast to continue through the weekend as another weak frontal
boundary approaches from the NW. Moderate to fresh NW breezes in
the southern waters are expected tonight into Saturday. A small
craft advisory remains in effect. As winds subside on Saturday,
steep northerly waves are forecast to continue through the day and
a small craft advisory remains in effect until 6 PM Saturday. A
persistent NW swell at 9 seconds around 7 feet will likely continue
into Saturday. A longer period W swell near 15 second around 3 ft
will arrive on Saturday. Larger combined seas (8 to 10 ft) are expected
to build early next week as northerly winds strengthen, especially
south of Cape Mendocino where a few gusts to 35 kt are possible
(50% chance). EYS/DB

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     Frost Advisory from 2 AM to 8 AM PDT Saturday for CAZ107-
     108-110-111-114.

NORTHWEST CALIFORNIA COASTAL WATERS...
     Small Craft Advisory from 5 PM this afternoon to 6 PM PDT
     Saturday for PZZ455-475.

&&

$$

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